The present embodiments relate to operating a communication network.
Communication networks are being used to an ever greater extent for measuring, controlling and regulating complex technical systems. By way of example, networks are increasingly used in motor vehicles in order to form vehicle control systems. Corresponding complex and safety-relevant technical systems make great demands on the availability of the control elements provided as network devices. When single components (e.g., sensors or control devices) fail, this must not result in the failure of the overall system. Particular relevance to safety applies to drive by wire systems, in which the steering wheel position is converted into wheel positions by electric motor using a network coupling of sensor, control and actuator devices.
In the past, redundant designs of particularly critical components have been used, so that in the event of an error, the respective backup or redundant component may undertake the respective task. When there are a plurality of redundant components, only one of the two or more control devices is to have the respective control sovereignty. Conflicting control commands are not to arise for the same control functionalities. It is therefore desirable for all the control components to have the same information or data in the network.
In this respect, errors in the form of inconsistent data, which may be corrupt in the event of data transmission via the network that is used, for example, are to be recognized. A standard network environment that is in widespread use is based on the Ethernet protocol. The use of Ethernet infrastructures has the advantage that standardized network devices and methods may be used. In the past, however, proprietary data buses were also used in order to link control components having internal redundancy (e.g., duplicate functionality) to one another.
By way of example, DE 102 43 713 A 1 discloses a redundant controller arrangement. In this case, controllers networked via a data bus that have redundant control functions are provided. The redundant controllers are coupled to the data bus via isolator switches, so that in a particular assessment situation the respective control device is connected or decoupled. In this case, DE 102 43 713 A1 provides redundant data bus systems, with redundant control components in a respective network device. A similar approach is followed by WO 2006/002695 A1. Based on the prior art, a duplicate communication system, in which information supplied by a subscriber is received by all the subscribers, is used in this respect. A drawback in this case is the use of duplicate data buses, such as FlexRay or CAN.